If you do some research on Yobit.net here (bitcointalk.org), you will find that lots of people got SCAMMED by using Yobit. Some people complained about missing funds, withdraw delays, other weird stuff. By the way, yobit is not consider as an exchange. Going back to PYN, why they can't get on binance/bittrex/OKex/Huobi? I mean they can't even get on cryptopia? C'mon
Count me in as a witness

I had all sorts of trouble with them. Wallet disabled, withdrawals not processed, support tickets ignored for an eternity etc.
I only did a trade once over the exchange and never had any problems with deposit/withdrawal and it has been more than a year, I ever traded on yobit.Luckily after all these reviews, I would avoid using the exchange.